An Interior Ministry spokesman claimed a law for its usage of drones was at its last period and also called on people to acquire the essential authorities clearance to make use of the apparatus "to get specific causes in permitted locations", state news agency SPA reported.
There was no information of where the king was.
According to an unnamed senior Saudi official cited by Reuters, however, King Salman was not at the palace but "at his farm in Al-Diriyah".
"Security personnel at the checkpoint dealt with it according to their orders and instructions in this regard", SPA added, implying that the drone had been shot down.
Government officials did not immediately respond to requests for comment on the whereabouts of the Saudi king and crown prince during the incident.
The authenticity of the videos could not be verified. As the Kingdom has not yet formally formed regulations for using drones.
The attacker, who was identified by the interior ministry as Mansour al-Amri, a 28-year-old Saudi national, was armed with a Kalashnikov rifle and three Molotov cocktails.
"Ongoing violence in the capital Riyadh and The_Fleeing_of_King_Salman raises concern #Gunfire_in_Al-Khuzami-neighborhood", Masarir tweeted alongside a video of what appeared to be scenes of unrest. Notable clerics also have been detained in a clear bid.
Saudi forces said they intercepted a rebel ballistic missile targeting kingdom's southern coastal city of Jizan on Friday, the second such strike in the area in over a week.
Those moves have helped Prince Mohammed consolidate his position in a country where power had been shared among senior princes for decades and religious figures exercised significant influence on policy.